Implementation of shutter control with an android application

I was given the task of writing a mobile application that would control an office shutter. The basis of the project was already there, the shutters of two companies could be controlled from one website at the same time. The problem with this was that every time they opened the office in the morning, they had to enter the IP address of the web interface into the browser and there were too many buttons.

A bit of hacking

Since I didn't make the previous system, I had to figure out how it works before starting to write the application. Since the website was available, I had an idea that a Javascript request could be sent from the frontend to another page, from which the shutter would receive impulses. The how was no longer important to me. If the same GET request were sent to that endpoint from an Android application, approximately the same thing would happen. So I looked at the source of the page and I was right. It really works as I imagined. In the picture below, I show how this system works.